hmm.. don't think the primary purpose of the garlic is to entice the flavour.
Garlic is used primary for the enhancement of immune system for the fishes.
However, not all fishes will consume fresh chopped garlic. So, you can also get those Garlic socking solution sold in LFS. Soak the fish food stuff in the garlic solution for around 10min and then feed.
As for my fishes, i use finely chopped fresh garlic and mixed with mysis or brine shrimp, together with seaweed.